1. Field of the Invention
This invention relates to brakes, and, more particularly, to a spring-set, centrifugally released brake for use in a linear actuator.
2. Disclosure of Related Art
In a linear actuator, a brake is often used to prevent "back driving" of the actuator when the actuator is at rest under an axial load (i.e., a load or force applied to an extension tube of the actuator along an axis of the extension tube). Such brakes are particularly useful in linear actuators that incorporate anti-friction bearings. Anti-friction bearings are desirable for use in linear actuators because they enable more efficient movement of loads. One disadvantage of anti-friction bearings, however, is that they increase the likelihood of "back driving" of the actuator. As a result, linear actuators that incorporate anti-friction bearings require an increased braking force to hold an axial load while the actuator is at rest. The application of this increased braking force produces a large friction brake drag that adds to the load of the actuator's motor when the actuator is in operation.
Conventional brakes used in linear actuators--both those with and without anti-friction bearings--also suffer from other deficiencies. First, the brakes are often expensive and require numerous parts. Second, the operation of the brakes is often complex and inefficient. For example, electrical power is often utilized to release the brake.
There is thus a need for a brake that will minimize or eliminate one or more of the above-mentioned deficiencies.